Mars Observer

Mars Observer was intended as a high-tech Mars orbiter to investigate
and chart the Red Planet's surface with modern camera equipment.

Launched successfully on September 25, 1992 by Titan IIIe-TOS from Cape Canaveral,
the spacecraft cruised well right up to Mars, but lost contact just at its arrival
on August 21, 1993, when it was to ignite its thrusters to enter Mars orbit. Its
fate is unknown: It may have blown up during ignition, destroyed by meteorite, or
simply frozen after having lost orientation.